The processors and other components of modem personal computers generate significant amounts of heat in operation and therefore require cooling. Generally, a fan is provided in the computer housing which provides a forced air flow within the housing. Individual components, such as the processor chip itself, which generate significant amounts of heat can be provided with heatsinks for dissipating heat generated by the component. Sometimes, the processor chip itself is cooled by the use of a fan heatsink, in which a fan is mounted on a heatsink on the processor package to blow air across the heatsink.
Whilst the use of a forced air flow can provide effective cooling and has the advantage that it can allow the computer to operate in more than one orientation, the fan necessarily generates undesirable noise. The noise generated is directly related to the speed of the fan and consequently to the degree of cooling provided by the forced air flow. Furthermore, the reliability of the fan may be reduced with higher fan speeds. For the above reasons, in the design of such systems it is desirable to try to reduce the speed of the fan or eliminate the use of a forced air flow entirely.
In another known cooling arrangement used in various types of electronic apparatus, at least part of the excess heat is transferred from within a housing to a heat sink mounted on the exterior of the housing which generates a cooling airflow by convection. For safety or aesthetic reasons such an external heatsink would normally be mounted to the rear of the housing, at least in products destined for use in offices or homes.
One problem with this arrangement is that such convective heatsinks usually comprise a set of parallel fins and will only operate effectively with the fins vertical. Such a finned heatsink mounted to the rear of a typical personal computer system unit would not allow the unit to operate correctly both in a desktop orientation and in a tower orientation, the two most common operating configurations for personal computers. It will be understood that in general, in a desktop configuration a computer system unit housing is wider than it is tall, so that a computer display may be placed on top of the housing. In a tower configuration, a computer system unit housing is taller than it is wide so that it may conveniently be placed on the floor beside a desk, the associated display being placed on the desk separate from the system unit.
The object of this invention is to provide an improved cooling arrangement for a personal computer and which, in particular, allows the computer to be operated in more than one operating orientation.